Investigation on Static Characteristics of Self-lubricated Aerostatic Thrust Bearing of Organic Rankine Cycle Turbine Driven by Nuclear Heat
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摘要: 微型反应堆搭配有机朗肯循环的技术路线是实现特殊场景多能供给的有效方案。在有机朗肯循环透平发电机组中使用有机工质自润滑气浮轴承可取消庞杂的油站系统，是提高系统紧凑性的有效措施。为探究有机工质自润滑气浮轴承的静态特性，本研究针对静压止推轴承，讨论了供气压力、供气温度和转速对轴承承载力和耗气量的影响规律，并进一步探究了节流形式、轴向间隙和润滑介质的影响。结果表明，不同工况下，气膜压力分布规律基本保持一致，沿径向从节流区域向出口处逐渐降低。在高供气压力、高进口温度和低转速下，轴承承载力均可保持在较高水平。在保证进气面积相同时，相比于小孔节流轴承，狭缝节流轴承的承载力较高而耗气量较小。随轴向间隙增大，气膜压力显著降低，承载力减小而耗气量增大。润滑介质对轴承的静态特性有一定影响，大部分工况下，R134a润滑介质轴承静态特性最优，环戊烷润滑介质轴承次之，R245fa润滑介质轴承最差。本研究结果可为有机工质自润滑气浮轴承的设计优化提供参考。Abstract: The nuclear power system of micro reactor with organic Rankine cycle is an effective approach to achieve multiple energy supply in special scenarios. The utilization of organic working fluid lubricated air bearing in organic Rankine cycle turbine generator set can eliminate the complex lubrication oil system, which is an effective measure to improve the compactness of the system. In order to investigate the static characteristics of organic working fluid lubricated air bearing, this paper focuses on the organic working fluid aerostatic thrust bearing, and the influence of inlet pressure, inlet temperature, and rotation speed on loading capacity and mass flow rate is discussed in detail. In addition, the effects of orifice type, axial clearance, and lubricating working fluid are further analyzed. The results show that under different operating conditions, the film pressure distribution characteristics remain basically consistent. The pressure gradually decreases radially from the orifice area to the outlet. Under the conditions with high inlet pressure, high inlet temperature and low rotation speed, the loading capacity can be kept at a high level. Compared to the thrust bearing with small orifice, bearings with slots have higher loading capacity and lower mass flow rate under the same inlet area. As the axial clearance increases, the film pressure significantly decreases, the loading capacity decreases, and the mass flow rate increases. The lubricating working fluid has a certain influence on the static characteristics. In most conditions, bearing lubricated by R134a performs the best static characteristics, followed by cyclopentane bearing, and R245fa bearing presents the relatively worst performance. The results in this paper can provide vital reference for the design optimization of organic working fluid lubricating bearings.
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图 1 静压止推轴承几何结构示意图
ro—轴承外径；ri—轴承内径；rs—狭缝径向位置；z—狭缝厚度；t—周向狭缝角度；ha—轴向间隙；Pi—供气压力；Po—出口压力
Figure 1. Geometric Structure of Aerostatic Thrust Bearing
图 2 静压止推轴承计算域网格示意图
Figure 2. Schematic Diagram of Computational Domain Grid of Aerostatic Thrust Bearing
图 3 周向狭缝节流轴承网格无关性验证结果
Figure 3. Grid Independence Results for Bearing with Circumferential Slit
图 5 3种节流形式轴承气膜压力分布
ω—旋转方向
Figure 5. Film Pressure Distribution for Three Orifice Types
图 6 3种节流形式轴承承载力和耗气量的变化
Figure 6. Variations of Loading Capacity and Mass Flow Rate for Three Orifice Types
图 8 3种轴向间隙轴承承载力和耗气量的变化
Figure 8. Variations of Loading Capacity and Mass Flow Rate for Three Axial Clearances
图 9 3种润滑介质轴承气膜压力分布
Figure 9. Film Pressure Distributions for Three Lubricating Working Fluids
图 10 3种润滑介质轴承承载力和耗气量的变化
Figure 10. Variations of Loading Capacity and Mass Flow Rate for Three Lubricating Working Fluids
表 1 静压止推轴承结构参数
Table 1. Structural Parameters of Aerostatic Thrust Bearing
参数 数值 参数 数值 轴承外径ro/mm 25 周向狭缝角度t 15° 轴承内径ri/mm 15 狭缝径向位置rs/mm 18.8 狭缝厚度z/μm 20 狭缝数目N 12 狭缝深度d/mm 4 径向狭缝长度l/mm 4.92 轴向间隙ha/μm 10/15/20 
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表 2 静压止推轴承运行参数
Table 2. Operating Parameters of Aerostatic Thrust Bearing
参数 数值 供气压力/MPa 0.2, 0.4, 0.6, 0.8, 1 供气温度/℃ 120, 140, 160, 180, 200 出口压力/MPa 0.1 转速/(r·min−1) 10000, 20000, 30000, 40000, 50000
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[1] 彭诗念,闫晓,张诚,等. 基于亚临界有机朗肯循环的核动力系统高温有机工质初选[J]. 中国基础科学,2021, 23(4): 21-29. doi: 10.3969/j.issn.1009-2412.2021.04.004 [2] REYNOLDS O. On the dynamical theory of incompressible viscous fluids and the determination of the criterion[J]. Proceedings of the Royal Society of London. Series A: Mathematical and Physical Sciences, 1995, 451(1941): 5-47. doi: 10.1098/rspa.1995.0116 [3] 王学敏,杜建军,李姗姗. 基于有限差分法对不同润滑介质下静压气体轴颈轴承性能研究[J]. 机械工程学报,2012, 48(3): 121-127. [4] YAO S M, TAN J B. Incompressible and analytical study on load-carrying capacity of a complex thrust gas bearing[J]. Tribology Transactions, 2006, 49(1): 102-107. doi: 10.1080/05698190500526905 [5] 李飞飞. 复合节流气体静压止推轴承静动态特性分析及实验研究[D]. 哈尔滨: 哈尔滨工业大学,2019. [6] 赖天伟,任雄豪,赵琪,等. 非均匀供气静压气体径向轴承的静特性分析[J]. 润滑与密封,2021, 46(12): 1-6. doi: 10.3969/j.issn.0254-0150.2021.12.001 [7] 郭雨,赖天伟,任雄豪,等. 润滑介质种类对气浮轴承性能的影响[J]. 润滑与密封,2021, 46(5): 1-5. doi: 10.3969/j.issn.0254-0150.2021.05.001 [8] LI L L, XIE Y H. Effect of operating condition and structural parameter in the hydrostatic thrust CO2 bearing[J]. Journal of Thermal Science, 2019, 28(3): 454-462. doi: 10.1007/s11630-019-1113-9 [9] GAD-EL-HAK M. The fluid mechanics of microdevices—the freeman scholar lecture[J]. Journal of Fluids Engineering, 1999, 121(1): 5-33. doi: 10.1115/1.2822013 [10] MCLINDEN M O, KLEIN S A, LEMMON E W, et al. NIST standard reference database 23: NIST thermodynamic and transport properties of refrigerants and refrigerant mixtures-REFPROP, version 6.0[S]. Gaithersburg: National Institute of Standards and Technology, 1998. [11] SUN A, LIU H Z, MA W Q, et al. Performance investigation of aerostatic thrusting gas bearing with discontinuous slot-restricted[C]//Proceedings of 2015 International Conference on Fluid Power and Mechatronics. Harbin: IEEE, 2015: 1252-1256. [12] MORI H. A theoretical investigation of pressure depression in externally pressurized gas-lubricated circular thrust bearings[J]. Journal of Basic Engineering, 1961, 83(2): 201-208. doi: 10.1115/1.3658925 -
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